Field of the Invention
The present invention relates to a tool changer with cover means configured to prevent foreign matter from getting into a turret.
Description of the Related Art
Tool changers are conventionally used to automatically change tools to be mounted on the spindle of a machine tool. A plurality of necessary work tools are previously set on this tool changer so that a tool specified for replacement in accordance with the machining state can be automatically mounted on the spindle of the machine tool.
Japanese Patent Applications Laid-Open Nos. 2010-99766, 5-38651, 6-739 and 2006-123116, Japanese Patent No. 3990441, etc., each disclose an example in which a machine tool is fitted with one such automatic tool changer for automatically changing tools. This tool changer comprises a turret with a plurality of grips for gripping the tools.
Conventionally, a turret is provided with cover means that prevents chips and cutting fluid from getting into the turret during workpiece machining. FIG. 11 shows an example of a conventional technique in which a tool changer comprising the turret with the cover means is attached to a machine tool.
In FIG. 11, a tool (not shown) is mounted on the distal end portion of a spindle 2 of a machine tool 1. Further, a Z-axis motor 3 is connected to the spindle 2 by a Z-axis ball screw so that the spindle 2 can be driven vertically by the Z-axis motor 3. Furthermore, the tool changer is provided with a turret 6 for use as a member for changing the tool.
The spindle 2 is provided with a turret cam 4 and a cam follower 5, whereby the angle of the turret 6 can be changed. The turret 6 comprises a turret mechanism portion 604 and a turret-inside mechanism portion 606, whereby the turret 6 can be rotated.
Further, a front cover 601 and a rear cover 602 are provided on the front and rear sides, respectively, of the turret 6, in order to prevent chips and cutting fluid from getting into the turret-inside mechanism portion 606 and adversely affecting it. The rear cover 602 comprises a truncated-cone portion 605 and an outer rear surface portion 603 behind it.
Since the turret cam 4 is provided on the spindle 2 in this tool changer, the turret 6 is subjected to a swinging motion by the cam follower 5 that follows the turret cam 4 as the Z-axis motor 3 is driven to move the spindle 2 vertically.
In the conventional automatic tool changers disclosed in the patent documents described above, the turret is fitted with a plurality of tools and is indexed to change a tool mounted on the spindle, so that the tool change can be performed rapidly and accurately. Since the front side of the turret and a turret base are only connected by simply providing a gap between them, the cutting fluid and chips produced during machining may possibly get into various parts of the turret and adversely affect them.
According to the conventional technique shown in FIG. 11, moreover, chips produced as a workpiece is machined and cutting fluid used in the machining may sometimes drop along the outer rear surface portion 603 of the rear cover 602 and get into the turret mechanism portion 604. When the turret 6 is swung, furthermore, the chips and cutting fluid collected on an upper part of the truncated-cone portion 605 of the rear cover 602 may get into the turret mechanism portion 604 in the same way.
Thus, in some cases, the rear cover of the conventional technique may not be able to fully prevent the chips and cutting fluid from getting into the turret mechanism portion 604.